1. Field of the Invention
The present invention generally relates to pothole safety guards for lifting machines, and particularly to a safety guard mechanism for a lifting device, such as a scissors-type aerial lift, that uses a helical screw and roller mechanism to deploy the safety guard for preventing the lifting device from tipping over when a pothole or similar tipping hazard is encountered.
2. Description of the Related Art
Aerial platforms allow users to perform work at or lift materials to elevated locations. Typically, a work platform comprises a scissor-style lift on which a platform is secured. The lift and platform are mounted on a motorized chassis or mainframe that is provided with wheels. While positioned on the platform, the user can control the elevation of the platform and the speed and direction of the chassis. When the platform is raised, the center of gravity of the aerial platform is raised, creating a risk that the device will tip over in high winds, or when the wheel slips into a pothole next to the wheel. Other lifting devices, such as backhoes and other construction equipment, have similar problems with stability. Such problems arise when one or more of the wheels hits a pothole, runs off a curb or encounters similar barriers that can cause the work platform to tip over causing damage and perhaps serious injury.
There are numerous anti-tipping deployment schemes, most having a plethora of moving parts that can lead to catastrophic failure of the system should any one of the parts malfunction. Most of the existing systems are linkages, rollers, air springs or springs, hinge pins, bolts and nuts and the like. Many of the functional parts involved in legacy systems are springs or gas springs designed to hold the safety guard when deployed.
If these springs fail when activated, the pothole safety guards will be freely suspended in the air, unable to perform their function. None of the existing designs has a self-lock security against spring failures. The art would certainly welcome an efficient device that would deploy anti-tipping members on a work platform, thereby preventing damage and/or injury.
Thus a safety guard mechanism for a lifting device solving the aforementioned problems is desired.